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调查许昌市主要彩叶树种种类,分析彩叶树种在许昌市的园林应用现状,并对彩叶植物在许昌地区的发展提出建议。
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文章通过对泰州市彩叶植物应用情况的调查与分析,提出了彩叶树种应用的建议,并展望了彩叶植物在泰州市园林中的广阔的应用前景。
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随着人类社会对生态环境建设的关注热情不断高涨,人们对园林绿地树种的多样性选择也表现出极大的兴趣。为了在绿化人居环境的基础上进一步美化生活、丰富景观,彩叶树种的选择与应用已成为当今国际范围内风景园林建设中的时尚潮流。就中国而言,近几年从国外引种栽培的彩叶园林树种就达数十种之多,这在提升我国园林绿化建设水准和文化内涵等方面显示了卓越的成效,其产业化开发的经济效益与社会效益均十分显著:如浙江萧山,已成为我国著名的彩叶园林树种生产繁育基地,彩叶园林树种也成为当地花农发家致富奔小康的主要生产资料;我国园林绿地建设中原有的自闭、落后局面正在被打破,彩叶园林树种的推广应用正在迅疾兴起,呈现出一片可持续发展的广阔前景。
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上海植物园典型群落景观美景度评价 总被引:1,自引:0,他引:1
在全面调查上海植物园植物群落的基础上,采用美景度评判法(SBE)对33个典型群落进行美学价值评价,结果表明其美景度值为-1.38~1.37。得分值≥ 0的有16个群落,其建群树种几乎全为落叶阔叶树、且多为3层结构,得分较高的群落建群树种主要包括栾树、旱柳、乌桕、香樟、银杏、柿树、合欢等,下层以彩叶或观花树种如红花檵木、海棠、杜鹃、日本晚樱、八仙花等为主。影响群落景观美学特点的因素主要有树种组成、色彩、垂直结构、群落与周围环境的协调度、树木的健康状况及林冠线变化度等。植物园的植物群落美景度评价是构建城市绿地群落的重要参考。
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合肥城市森林减少大气污染的效果 总被引:19,自引:6,他引:13
树木主要通过气孔吸收气态污染物,同时通过滞留空气中的微粒而减轻污染,树木较高的覆盖率可能会减少挥发性有机物的释放量,定量研究表明,合肥市1998年吸收空气污染物约为151.5t,树木7月份(着叶季节)吸收污染量高达20t,具有相对较低臭氧生成潜力的植物有香樟属、女贞属、紫薇属、罗汉松属和李属。合肥城市森林总体的臭氧指标得分值为92.4。
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秋色叶树种进入秋季后,其叶片的色泽较为均匀地由绿色转为其它颜色,具有较强的观赏价值。应用这一特性,在园林景观建设中点缀种植,可提供良好的视觉效果。文章介绍了常见秋色叶树种的品种、色泽、地域及其在园林景观中的栽植方式及应用。 相似文献
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The effectiveness of spraying foliage with urea to provide nitrogen (N) to augment the seasonal internal cycling of N in young nectarine trees (Prunus persica (L.) Batsch var. nectarina (Ait. f. Maxim.), cv. Stark Red Gold) was studied. One-year-old trees were grown with contrasting N supplies during the summer and foliage was sprayed with a 2% urea solution labeled with (15)N just before leaf senescence started. After leaf abscission had finished, the trees were repotted in sand and given no further N. Remobilization of both labeled and unlabeled N for leaf growth the following spring was quantified. Leaves absorbed between 58 and 69% of the (15)N intercepted by the canopy irrespective of tree N status. During leaf senescence, the majority of (15)N was withdrawn from the leaves into the shoot and roots. Remobilization of (15)N the following spring was also unaffected by tree N status. About 38-46% of (15)N in the trees was recovered in the new growth. More unlabeled N (derived from root uptake) was remobilized for leaf growth in the spring than was withdrawn from leaves during canopy senescence the previous autumn. Therefore, soil-applied N augmented N storage pools directly, and contributed more to N remobilization the following spring than did foliar-absorbed (15)N. 相似文献
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We measured the seasonal and temperature responses of leaf photosynthesis and respiration of two co-occurring native New Zealand tree species with contrasting leaf phenology: winter-deciduous fuchsia (Fuchsia excorticata J. R. Forst & G. Forst) and annual evergreen wineberry (Aristotelia serrata J. R. Forst & G. Forst). There was no difference in the amount of nitrogen per unit leaf area (Narea, range 40-160 mmol m-2, P = 0.18) or specific leaf area (S, range 8-27 m2 kg-1, P = 0.87) in summer leaves of wineberry or fuchsia. The amount of nitrogen per unit leaf area and S varied significantly with height of leaves in the canopy for both species (r2 range 0.61-0.87). Parameters describing the maximum rates of rubisco carboxylation (Vcmax) and electron transport (Jmax) were related significantly to Narea, and were 60% higher on average in spring and summer leaves than in autumn and winter leaves for both species. The seasonal effect remained significant (P < 0.001) when Narea was included in a regression model, indicating that seasonal changes were not only due to changes in Narea. Values for Vcmax and Jmax were 30% lower in wineberry leaves than in fuchsia leaves on average, although the difference ranged from 15% in summer leaves to 39% in autumn leaves. Activation energies describing the temperature dependence of Vcmax and Jmax in wineberry were 111 and 114% of corresponding values for fuchsia (Ea (Vcmax) = 39.1 kJ mol-1, Ea (Jmax) = 32.9 kJ mol-1). Respiration at night was the same (P = 0.34) at 10 degrees C for both species (R10 = 0.7 micromol m-2 s-1), although activation energies (E0) were higher in wineberry than in fuchsia (47.4 and 32.9 kJ mol-1 K-1, respectively). These results show that rates of photosynthesis are higher in winter-deciduous fuchsia than in annual evergreen wineberry. 相似文献
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Autumnal changes in organic-S, sulfate-S, total-S and the ratios of organic-S to total-N and sulfate-S to organic-S were followed in leaves and adjacent bark of actinorhizal (Frankia-nodulated) black alder (Alnus glutinosa (L.) Gaertn.) and eastern cottonwood (Populus deltoides Bartr. ex Marsh.) trees growing on a minespoil site high in extractable soil sulfate, and in black alder and white basswood (Tilia heterophylla Venten.) trees growing on a prairie-derived soil in Illinois. Organic-S concentrations decreased significantly (P < 0.05) during autumn only in foliage of trees growing on the prairie-derived soil where losses of leaf organic-S were 65% for black alder and 100% for white basswood. Leaf sulfate concentrations were relatively stable throughout autumn in white basswood growing on prairie-derived soil and in black alder at both sites. Sulfate-S concentrations in leaves were significantly (P < 0.05) higher in trees at the minespoil site than in trees growing in the prairie-derived soil (5.1 mg g(-1) for the minespoil site and 1.2 mg g(-1) for the prairie-derived soil), and in the non-actinorhizal species during late summer. During the autumn, the ratio of organic-S to total-N doubled in leaves of eastern cottonwood at the minespoil site, but in black alder and white basswood growing on the prarie-derived soil, it decreased by 60 and 74%, respectively. Organic-S concentrations in bark increased more during autumn in species unable to fix atmospheric N(2), than in black alder. The results suggest that patterns of autumnal translocation of leaf S can be site-dependent and that leaf S and leaf N are, at least in part, translocated independently in the fall. Black alder and eastern cottonwood seemed to incorporate sulfate-S readily into organic substances in leaves when grown in soils with a high sulfate content. 相似文献
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We quantified leaf phenologies of saplings and overstory trees of sugar maple (Acer saccharum Marsh.) and American beech (Fagus grandifolia Ehrh.), and the shrub hobblebush viburnum (Viburnum alnifolium Marsh.) in a 72-year-old northern hardwood forest. Seasonal changes in irradiance in the shrub layer, and in the leaf CO(2) exchange of viburnum, and sugar maple and beech saplings were also measured. Leaf expansion occurred earlier in the spring and green leaves were retained later in the autumn in saplings and shrubs than in overstory trees. During the spring light phase (before overstory closure), large CO(2) gains by all three shrub-layer species occurred as a result of a combination of relatively large leaf area, high photosynthetic capacity, and high irradiance. Throughout the summer shade phase, photosynthetic capacity at a given irradiance remained relatively constant, but CO(2) gain was typically limited by low irradiances. Even though irradiance in the shrub layer increased during the autumn light phase as the overstory opened, CO(2) gains were modest compared to springtime values because of declining leaf area and photosynthetic capacity in all three species. The CO(2) gains during the spring light phase, and to a lesser extent during the autumn light phase, may be important to the carbon balance and long-term persistence of saplings and shrubs in the usually light-limited shrub layer of a northern hardwood forest. Therefore, for some late-successional species, leaf phenology may be an important characteristic that permits their long-term persistence in the shrub layer of mature northern hardwood forests. 相似文献
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观赏石榴也称花石榴,是以观赏为主的石榴品种总称,其树形优美,干形扭曲,苍劲古朴,千姿百态,自然成景,叶碧绿而有光泽,花朵硕大,重瓣,花色丰富,花期长,果实色泽鲜艳,是夏、秋季节不可缺少的观赏花卉.可种植于庭院、公园、居民小区等处,是典型的观赏树种,又是制作树桩盆景和观果盆景的良好树种. 相似文献
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研究通过对两种藤本植物叶片的叶面积、比叶面积、叶厚度、气孔参数和叶脉密度的测定来分析不同季节下植物叶片的性状差异以及其性状之间的联系,为探讨植物叶片性状对环境适应的可塑性提供理论基础,同时也为藤本植物在园林中的应用提供依据。结果表明:(1)两种藤本植物叶片各性状随着季节变化呈现显著差异(P<0.5),季节变化对五叶地锦的影响大于爬山虎。两种植物的叶面积和叶厚度均夏季为最高;五叶地锦叶片气孔长度和气孔密度随季节变化先减小后增大;爬山虎叶片气孔长度随季节变化逐渐增大,气孔密度先减小后增加,春季气孔密度最大;叶脉密度均为春季最大,夏季和秋季逐渐降低。(2)两种植物叶片各性状之间存在一定的联系,但是显著性因品种和季节变化而不同。 相似文献
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Canopy photosynthetic capacity, measured as leaf maximum carboxylation rate (V (cmax)), is a key factor in ecosystem gas exchange models applied at different scales. We report seasonal and interannual variations in V(cmax) of natural beech stands (Fagus crenata Blume) along an altitudinal gradient in the temperate climate zone of Japan. Estimates are based on 6 years of gas exchange measurements. Pronounced seasonal and interannual variations in V(cmax) normalized to 25 degrees C (V(c,25)) were found for sun leaves. The seasonal pattern of V(c,25) generally followed an inverse parabolic curve, with an increase in spring, peak values in the middle of the growth period and a decline in autumn. Leaf nitrogen concentration (N(l)) and leaf mass per area were significantly related to V(c,25) during spring and summer, but were unrelated in autumn when V(c,25) declined. Annual peak V(c,25) ranged from 40.1 to 97.0 micromol m(-2) s(-1) and varied over as much as a twofold range at a particular site. Annual peak V(c,25) occurred about 28 days before annual peak N(l), with which it was poorly related. Our results show that it can be inappropriate to include constant values of photosynthetic parameters in ecosystem gas exchange models. 相似文献
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Water-use strategies in two co-occurring Mediterranean evergreen oaks: surviving the summer drought 总被引:1,自引:0,他引:1
David TS Henriques MO Kurz-Besson C Nunes J Valente F Vaz M Pereira JS Siegwolf R Chaves MM Gazarini LC David JS 《Tree physiology》2007,27(6):793-803
In the Mediterranean evergreen oak woodlands of southern Portugal, the main tree species are Quercus ilex ssp. rotundifolia Lam. (holm oak) and Quercus suber L. (cork oak). We studied a savannah-type woodland where these species coexist, with the aim of better understanding the mechanisms of tree adaptation to seasonal drought. In both species, seasonal variations in transpiration and predawn leaf water potential showed a maximum in spring followed by a decline through the rainless summer and a recovery with autumn rainfall. Although the observed decrease in predawn leaf water potential in summer indicates soil water depletion, trees maintained transpiration rates above 0.7 mm day(-1) during the summer drought. By that time, more than 70% of the transpired water was being taken from groundwater sources. The daily fluctuations in soil water content suggest that some root uptake of groundwater was mediated through the upper soil layers by hydraulic lift. During the dry season, Q. ilex maintained higher predawn leaf water potentials, canopy conductances and transpiration rates than Q. suber. The higher water status of Q. ilex was likely associated with their deeper root systems compared with Q. suber. Whole-tree hydraulic conductance and minimum midday leaf water potential were lower in Q. ilex, indicating that Q. ilex was more tolerant to drought than Q. suber. Overall, Q. ilex seemed to have more effective drought avoidance and drought tolerance mechanisms than Q. suber. 相似文献